Synthetic antiprotozoal thiazolide drug induced apoptosis in colorectal cancer cells: implications of IL-6/JAK2/STAT3 and p53/caspases-dependent signaling pathways based on molecular docking and in vitro study

Mol Cell Biochem. 2020 Jun;469(1-2):143-157. doi: 10.1007/s11010-020-03736-4. Epub 2020 Apr 30.


Colorectal cancer (CRC) is a global pressing healthcare priority. Dysregulation of the IL6/JAK2/STAT3 and p53/caspase downstreaming pathways are significantly involved in the progression of CRC, and mainly affecting apoptosis. Discovery of new anti-cancer agents is laborious, time consuming, and costly with obvious socioeconomic burden. In the present study, we are proposing new molecular insights on the anti-proliferative and apoptotic therapeutic effects of nitazoxanide (NTZ) on CRC. NTZ is FDA-approved thiazolide antiparasitic agent, which has excellent safety and pharmacokinetic profiles. The molecular docking study revealed that NTZ has better binding affinity and docking score against JAK2 and BCL2 proteins compared to 5-Fluorouracil, which is the standard drug for treatment of CRC. The current in vitro work on a human HCT116 cell line displayed that NTZ had lower IC50 value (11.20 µM) than 5-flurouracil (23.78 µM), and NTZ induced a statistically significant down-regulation of IL6/JAK2/STAT3. NTZ also modulated significantly the p53/caspases-dependent signaling pathways, leading to enhancement of apoptosis and an increase of DNA fragmentation. Moreover, NTZ regulated the Bcl-2 gene family and promoted the loss of mitochondrial function which was depicted by release of cytochrome c (Cyt c), and caspase activation in apoptotic HCT116 cells. Additionally, NTZ was able to reduce the expression of VEGF in CRC cell line, which needs future thorough molecular investigations. In conclusion, our findings provided a novel evidence that NTZ could be a dual potential IL6/JAK2/STAT3 signaling inhibitor and p53/caspases-dependent pathway activator in CRC cell line. These potentials support further exploratory molecular researches targeting the therapeutic roles of NTZ in CRC; individually and simultaneously with current approved chemotherapeutic regimens.

Keywords: Apoptosis; Colorectal cancer; IL6/JAK2/STAT3; Molecular docking; Nitazoxanide; p53/caspases.

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Antiprotozoal Agents / pharmacology
  • Apoptosis / drug effects*
  • Caspases / metabolism
  • Cell Cycle / drug effects
  • Cell Survival / drug effects
  • Colorectal Neoplasms / drug therapy*
  • Colorectal Neoplasms / metabolism
  • Cytochromes c / metabolism
  • Fluorouracil / chemistry
  • Fluorouracil / pharmacology
  • HCT116 Cells
  • Humans
  • Hydrogen Bonding
  • Hydrophobic and Hydrophilic Interactions
  • Inhibitory Concentration 50
  • Interleukin-6 / metabolism*
  • Janus Kinase 2 / chemistry
  • Janus Kinase 2 / metabolism*
  • Molecular Docking Simulation
  • Nitro Compounds
  • Proto-Oncogene Proteins c-bcl-2 / chemistry
  • Proto-Oncogene Proteins c-bcl-2 / metabolism
  • STAT3 Transcription Factor / metabolism*
  • Signal Transduction / drug effects
  • Thiazoles / chemistry
  • Thiazoles / pharmacology*
  • Tumor Suppressor Protein p53 / metabolism*
  • Vascular Endothelial Growth Factor A / metabolism


  • Antineoplastic Agents
  • Antiprotozoal Agents
  • Interleukin-6
  • Nitro Compounds
  • Proto-Oncogene Proteins c-bcl-2
  • STAT3 Transcription Factor
  • STAT3 protein, human
  • Thiazoles
  • Tumor Suppressor Protein p53
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • Cytochromes c
  • JAK2 protein, human
  • Janus Kinase 2
  • Caspases
  • nitazoxanide
  • Fluorouracil